ADAMS-JONES MOST IMPROVED MICROSCOPE (large variety)

MODEL: 'JONES MOST IMPROVED'

DATE: 1st Qtr 19th C.

MAKER: DOLLOND

SERIAL NUMBER: None

COUNTRY OF ORIGIN: ENGLAND

DESCRIPTION:

This microscope (unfortunately no longer in my collection), arises from a folding three-legged tripod with Dollond's signature. The gently curving tapering pillar attaches to the inclining straight limb by a
compass joint. Focus is to the stage by rack and pinion acting on the
front side of the limb which has the rack machined into it. The
substage condenser and mirror slide on box-shaped fittings along the
limb. They can be locked in place by small knurled knobs. There is a
removable substage cone diaphragm. The stage is fitted with a U-shaped
stage clip which attaches through the stage with two sliding pins,
allowing it accommodate a variety of thicknesses. There is also a
Bonani-type spring stage to accept bone sliders. There are three holes
off small extensions of the flat stage to accept accessories. In this
case a stage forceps, a magnifying glass, and a bullseye condenser are
all shown attached. The arm fits through a slot in the limb and a
knurled knob at the top of the limb acts on a compression fitting to
hold the arm in place. The optical tube has a rotating wheel of
objectives with each showing a number in a hole of the objective disc.
Other accessories include a fish-plate with green ribbon,
bone sliders, and a 'talc box' containing mica coverslips (talcs) and
brass circlips to hold them in place. Broken down it is all housed in a green velvet lined fitted hardwood case of dark brown color.

HISTORY OF THE JONES MOST IMPROVED MICROSCOPES

This is the larger of the two versions of this form of microscope, a smaller version
of which still resides in this collection. William and Samuel Jones
became famous instrument makers of the early nineteenth century. Among
their microscopes were simple botanical microscopes as well as more
complex instruments. George Adams Jr devised his 'Universal Compound
Microscope' from which the 'Jones Most Improved' was clearly derived.
After devising the 'Jones Improved' microscope, W & S Jones then
came out with the 'Jones Most-Improved' Microscope. It was sold in two
sizes and this is the larger version. It was a standard microscope of
the preachromatic era, and even beyond, as in some cases they were
adapted for achromatic objectives. Although an improvement over
flimsier designs, this was still not the best design for critical high
power work with achromatic optics however, and soon was replaced by
Lister-limb and Bar-limb microscopes. The Jones' succeeded Adams who
first described his version about 1787 in his 'Essays on the
Microscope'.